Microbiological Causes Of Defects In Fetal Development And Miscarriage

During pregnancy many agents can be teratogenic i.e. can be dangerous for embryo or fetus and cause differentiated adverse effects. Teratogenic agents include substances (e.g. many pharmaceuticals, mycotoxins – e.g. aflatoxins and ochratoxin A), radiation (e.g. X/RTG, γ) and infectious agents. The latter include bacteria (e.g. Listeria monocytogenes, Treponema pallidum), protozoa (e.g. Toxoplasma gondii) and viruses (e.g. ZIKV, parvovirus B19, herpesviruses: CMV, HSV, VZV). Quite a few pathogens can be vertically transmitted, i.e. through placenta (poorly understood mechanism), but not all are typical teratogenic agents (TORCH group). Infection during gestation can be oligosymptomatic or asymptomatic for the mother, nevertheless can also be fatal for the child, causing among others IUGR, SNHL, malformation (e.g. microcephaly, limb defects), abortion. Some (but not all) of these abnormalities can be non-invasively diagnosed by ultrasonography (USG) and prevented by vaccination (in case of the rubella and varicella). In some countries routine serological diagnostics for selected pathogens are performed during pregnancy. Generally transplacental transmission occur mostly during initial (primary) infection and are most dangerous during the first and second trimester (intensive morphogenesis and organogenesis). Conversely chance of fetus infection usually increases with time and is highest in the third trimester.

1. Introduction. 2. Placenta. 3. Preterm delivery and vaginosis. 4. TORCH group. 5. Teratogenic microorganisms and viruses. 5.1. Bacteria. 5.2. Protozoa. 5.3. Viruses. 6. Mycotoxins. 6.1. Description of selected mycotoxins. 7. Summary